1. Field of the Invention
This invention relates to a method for selecting a plurality of graphic primitives displayed on a display screen for image processing and a recording medium.
2. Related Art
An image processing system for drawing a picture on a display screen using a graphic software on a computer such as a personal computer has been known. Such prior art system draws a plurality of graphic primitives including a rectangle and a circle for displaying on a display screen. As to the display position of the graphic primitive, the displayed graphic primitive can be moved by a dragging process (moving a pointing device while a click button is held depressed) of a pointing device such as a mouse. With such picture drawing process, a plurality of graphic primitives may be overlapped. When the internal area of a graphic primitive is solidly painted with a certain color, an overlapping portion of a graphic primitive drawn earlier is hidden by a graphic primitive drawn or moved later.
This is because graphic primitive data for display is stored by being overwritten with later graphic primitive data so that the overwriting graphic data is displayed. In an extreme case, the graphic primitive 101 is entirely hidden by the graphic primitive 100 as shown in FIG. 3. Therefore, when the user wants to select the graphic primitive 101, the user will perform an operation of selecting the graphic primitive 101 by moving the graphic primitive 101 to display a portion of the graphic primitive 100 or the position characterizing the graphic primitive, for example, the contour line and then pointing that portion by a pointing device.
Because the above operation is cumbersome for a user, a graphical user interface has been proposed which employs a graphic primitive selecting method in which overlapping portions are pointed by operating the click button to select a graphic primitive immediately behind the foremost graphic primitive and, by further pointing the portions, graphic primitives next behind are selected in sequence. Incidentally, this selecting method has also proposed a method of allowing said graphic primitive next behind to be selected by clicking the click button of a pointing device while operating a specific key of the keyboard
Because a graphic primitive entirely hidden by a fore graphic primitive is not known unless the fore graphic primitive is moved out or the sequence of overlap is changed in the graphic primitive selecting method of selecting each graphic primitive behind one after the other by each operation of the click button of the pointing device, many operations are required until the user obtains a desired graphic primitive when many overlapping graphic primitives are displayed.
It is therefore an object of this invention to provide a method of selecting a graphic primitive which enables a graphic primitive hidden by the fore graphic primitive displayed to be selected easily and a recording medium.
To achieve the above objective, the invention provides a graphic primitive selecting method for selecting a graphic primitive displayed on a display screen by a pointing device comprising; storing graphic primitive information indicating the position and the shape of said graphic primitive in a memory device, extracting the graphic primitive information of the graphic primitive including the position pointed by the pointing device from the graphic primitive information stored in said memory device when pointing is effected by the pointing device, detecting a graphic primitive which is included in one or more graphic primitives among the graphic primitive indicated by the extracted graphic primitive information and treating the detected graphic primitive as a graphic primitive selected by the pointing device.
The invention also provides a computer readable recording medium storing therein a program for selecting a graphic primitive by a pointing device from a plurality of graphic primitives which are stored in a computer memory device as a plurality of graphic primitive information including at least information of display position and the shape and displayed on a display screen of said computer, said program comprising: (a) program code means instructing said computer to recognize the position information indicated by said pointing device, (b) program code means for instructing said computer to extract a graphic primitive information including the position indicated by said position information and, (c) program code means for instructing said computer to detect a graphic primitive which is included in one or more graphic primitives among graphic primitives indicated by said extracted graphic primitives.